Systems and methods for improving sleep disordered breathing

ABSTRACT

A neuromodulation system is provided herein. The system can include a cuff electrode, an electronics package, which can be part of a neuromodulation device; an external controller; a sensor; and a computing device. The neuromodulation device can include an antenna including an upper and a lower coil electrically connected to each other in parallel. The computing device can execute a closed-loop algorithm based on physiological sensed data relating to sleep.

TECHNICAL FIELD

An electrical stimulation system for improving sleep disorderedbreathing is provided.

BACKGROUND

Obstructive sleep apnea (OSA) is the most common type of sleep apnea andis characterized by repeated episodes of complete or partialobstructions of the upper airway during sleep, despite the effort tobreathe, and is usually associated with a reduction in blood oxygensaturation. Individuals with OSA are rarely aware of difficultybreathing, even upon awakening. It is often recognized as a problem byothers who observe the individual during episodes or is suspectedbecause of its effects on the body. OSA is commonly accompanied withsnoring. OSA can be associated with symptoms during the daytime (e.g.excessive daytime sleepiness, decreased cognitive functions). Symptomsmay be present for years or even decades without identification, duringwhich time the individual may become conditioned to the daytimesleepiness and fatigue associated with significant levels of sleepdisturbance. Individuals who generally sleep alone are often unaware ofthe condition, without a regular bed-partner to notice and make themaware of the signs.

The most widely used current therapeutic intervention for treating OSAis positive airway pressure whereby a breathing machine pumps acontrolled stream of air through a mask worn over the nose, mouth, orboth. The additional pressure holds open the relaxed muscles. There areseveral mechanisms for treating OSA with positive airway pressuretherapy. The most common treatment involves the use of continuouspositive airway pressure (CPAP) machines. CPAP machines are worn by theOSA patient at nighttime during sleep, with the patient wearing a maskconnected by hose to an air pump that maintains positive airwaypressure.

Neurostimulation therapy can be an alternative for patients who cannotuse a continuous positive airway pressure device. One neurostimulationsystem senses respiration and deliver mild electrical stimulation to thehypoglossal nerve (HGN) in order to increase muscle tone at the back ofthe tongue so it will not collapse over the airway. The HGN innervatesthe tongue musculature. It provides motor control for the muscles of thetongue and helps with important voluntary and involuntary functions likeswallowing, speaking, and mastication. Stimulating the HGN can restorethe tone to key tongue muscles that, when relaxed, can lead toobstructive sleep apnea.

Conventional HGN neurostimulation systems utilize stimulation leadsimplanted in the patient's neck/throat, with electrodes touching, e.g.,a cuff electrode that surrounds the HGN or in close proximity to theHGN. The leads are connected via wire to a pulse generator implantedunder the skin in the patient's chest. From time-to-time, the pulsegenerator is surgically accessed for battery changes. The systemincludes a handheld patient controller to allow it to be switched onbefore sleep.

While HGN neurostimulation therapy has proven to be an effectivetreatment for OSA, the bulk of the conventional systems and the degreeof invasiveness in implanting, using, and maintaining the system isundesirable.

SUMMARY

A neuromodulation system is provided herein. In an aspect, aneuromodulation system comprises a nerve cuff electrode comprising acuff body having at least one stimulating electrical contact disposedthereon configured to deliver a stimulation signal to a target site. Thesystem also includes a sensor configured to be implantable adjacent toan anterior lingual muscle and configured to record physiological data.The system further includes an antenna configured to produce an inducedcurrent in response to being disposed in an electromagnetic field andcomprising an upper and a lower coil electrically connected to eachother in parallel. The system further includes an electronics packagecomprising electrical components to control the application of astimulation signal via the at least one stimulating electrical contactof the nerve cuff electrode. An external controller is provided whichcomprises a control unit and a power mat that supports one or more powertransmission coils that are excitable to produce an electromagneticfield for inducing electrical current in the antenna to power theelectronics package. The system also includes a computing devicecomprising a non-transitory memory storing instructions and a processorto access the non-transitory memory and execute the instructions. Suchinstructions include monitoring the physiological data recorded by thesensor, identifying a trigger within the physiological data, wherein thetrigger is identified as a biomarker for a physiological conditionrelated to sleep, and applying a rule-based classification to thetrigger to determine whether one or more parameters of the stimulationsignal should be altered based on the biomarker and altering the one ormore parameters of the stimulation signal in response to the biomarker.In certain aspects, the sensors can comprise a plurality of sensorsdisposed on the lead body of a neuromodulation lead.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an example configuration of aneuromodulation system according to an aspect of the present disclosure.

FIG. 2 is a schematic illustration of an implantable neuromodulationdevice of an implantable stimulation system according to an aspect ofthe present disclosure.

FIG. 3 is a schematic illustration of a neuromodulation device accordingto an aspect of the present disclosure.

FIG. 4 . is a schematic illustration of a portion of a neuromodulationdevice according to an aspect of the present disclosure.

FIG. 5 is a section view taken generally along line 3-3 of FIG. 3 ,illustrating an antenna portion of the implantable neuromodulationdevice.

FIG. 6 is a schematic illustration depicting an exemplary configurationof a sensing lead or stimulation lead of a neuromodulation deviceaccording to an aspect of the present disclosure.

FIG. 7 is a schematic illustration depicting an exemplary configurationof a sensing lead or stimulation lead of aneuromodulation deviceaccording to an aspect of the present disclosure.

FIGS. 8A-8B are schematic illustrations depicting an exemplaryconfiguration of an antenna portion of a neuromodulation deviceaccording to an aspect of the present disclosure.

FIGS. 9A-9C are schematic illustrations depicting exemplaryconfigurations of a power mat portion of a neuromodulation systemaccording to an aspect of the present disclosure.

FIG. 10 is a block diagram of an example system that can provide neuralstimulation according to a closed loop algorithm to treat sleepdisordered breathing (SDB), which can be part of the system of FIG. 1 .

FIG. 11 is a block diagram of an example of the computing device shownin FIG. 11 .

FIG. 12 is a process flow diagram of an example method for providingneural stimulation according to a closed loop algorithm to treat SDB,including OSA, according to an aspect of the present disclosure.

DETAILED DESCRIPTION

As used herein with respect to a described element, the terms “a,” “an,”and “the” include at least one or more of the described elementincluding combinations thereof unless otherwise indicated. Further, theterms “or” and “and” refer to “and/or” and combinations thereof unlessotherwise indicated. By “substantially” is meant that the shape orconfiguration of the described element need not have the mathematicallyexact described shape or configuration of the described element but canhave a shape or configuration that is recognizable by one skilled in theart as generally or approximately having the described shape orconfiguration of the described element. As used herein, “stimulate” or“modulate” in the context of neuromodulation includes stimulating orinhibiting neural activity. A “patient” as described herein includes amammal, such as a human being. By “improving,” the patient's medicaldisorder is better after therapy than before therapy. As used herein,the terms, “inferior,” “superior,” “cranial,” and caudal refer toanatomical planes and directions when the patient is in a standardanatomical position. Similarly, the terms “left” and “right” refer tothe position of elements that correspond to the left and right side of apatient's body in a standard anatomical position. By “integral” or“integrated” is meant that the described components are fabricated asone piece or multiple pieces affixed during manufacturing or thedescribed components are otherwise not separable using a normal amountof force without damaging the integrity (i.e. tearing) of either of thecomponents. As used herein, a “neuromodulation device” is a device thatis not implanted in the oral cavity of a patient.

The present disclosure relates to an implantable electrical stimulationor neuromodulation system, which can be used to provide a variety ofelectrical therapies, including neuromodulation therapies such as nerveand/or muscle stimulation. Stimulation can induce excitatory orinhibitory neural or muscular activity. Such therapies can be used atvarious suitable sites within a patient's anatomy. In one exampleimplementation, the system can be used to treat sleep disorderedbreathing (SDB) including obstructive sleep apnea (OSA) vianeuromodulation of the hypoglossal nerve (HGN) and/or other nerves thatinnervate anterior lingual muscles such as protruser muscles; othermuscles of the tongue; and/or pharyngeal muscles, such as the posteriorpharyngeal walls.

Referring to FIG. 1 , in an embodiment, a neuromodulation system 11 isprovided that include a stimulator 13, a sensor 15, an antenna 17, anelectronics assembly 19, an external controller 21, and an internalcomputing device 27.

As described in more detail below, stimulator 13 can have a stimulatingelectrical contact disposed thereon configured to deliver a stimulationsignal to a stimulation site. The neuromodulation system can include aplurality of stimulators and a plurality of stimulating electricalcontacts disposed on each stimulator. Sensor 15 can have a sensingcontact disposed thereon configured to be implantable adjacent to asensing site and configured to record physiological signals. Theneuromodulation system can comprise a plurality of sensors and aplurality of sensing contacts on each sensor. For example, theneuromodulation system can comprise a first cuff lead having a cuff bodycomprising a plurality of stimulating electrical contacts disposedthereon and a second cuff lead having a cuff body comprising a pluralityof stimulating electrical contacts disposed thereon. The sensor cancomprise a sensing lead having a lead body comprising a plurality ofsensing contacts disposed thereon. The first cuff lead can have a cuffbody sized and configured to at least partially wrap around a firstnerve branch site comprising a hypoglossal nerve branch distal to thehypoglossal nerve trunk. The second cuff lead can have a cuff body sizedand configured to at least partially wrap around a second nerve branchsite proximal to the first nerve branch site. In certain aspects, thestimulator is a stimulating lead and the sensor is a sensing lead. Bothleads can be operably coupled to the electronics assembly and theelectronics assembly can be operably coupled to the antenna. The antennacan be configured to supply electrical current to the electronicsassembly to power the electronics assembly. The stimulating lead, thesensing lead, the electronics assembly, and the antenna can be parts ofa single neuromodulation device. The antenna can be located at aproximal end of the neuromodulation device, the electronics assembly canbe operably coupled to the antenna, and the stimulating lead and sensinglead can extend distally from the electronics assembly. In certainaspects, the sensor can be a sensing lead comprising a lead body with aright portion, a left portion, and an intermediate portion defining anapex of the lead body. A left set of sensors can be disposed on the leftportion of the lead body and a right set of sensors can be disposed onthe right portion of the lead body. The lead body can be biased towardsan omega shape when the neuromodulation lead is fully deployed and theintermediate portion of the lead body can be biased towards an inferiorposition relative to the left and right sensor sets when theneuromodulation lead is fully deployed.

Antenna 17 can be configured to produce an induced current in responseto being disposed in an electromagnetic field. The antenna can comprisean upper and a lower coil electrically connected to each other inparallel.

Electronics assembly 19 can comprise electrical components to controlthe application of the stimulation signal via the stimulating electricalcontact of the stimulator and sensing of the physiological signal by thesensor. External controller 21 can comprise control unit 23 and powertransducer 25 that supports a power transmission coil that is excitableto produce an electromagnetic field for inducing electrical current inthe antenna to power the electronics assembly. The power transducer canbe a mat as described in more detail below.

Internal computing device 27 can comprise a non-transitory memorystoring instructions and a processor to access the non-transitorymemory. The processor can execute the instructions to at least monitorthe physiological signals recorded by the sensor and identify a triggerwithin the physiological signals, where the trigger is identified as abiomarker for a condition related to sleep. In certain aspects, thetrigger indicates a change in phasic and/or tonic genioglossus muscleactivity during respiration. The processor can further executeinstructions to apply a rule-based classification to the trigger todetermine whether one or more parameters of the stimulation signalshould be altered based on the biomarker and to alter the one or moreparameters of the stimulation signal in response to the biomarker. Incertain aspects, the rule-based classification is adaptive. The initialrules of an algorithm used by the rule-based classification can bedetermined based on historical values for a population, historicalvalues for a patient, and/or patient derived values.

In certain aspects, a method of improving sleep disordered breathing ina patient suffering therefrom is provided. Such a method can compriseobtaining a neuromodulation system as described above and herein. Themethod can further include placing the stimulator on a stimulationtarget site comprising a trigeminal nerve or a branch thereof, a facialnerve or a branch thereof, a glossopharyngeal nerve or a branch thereof,a vagus nerve or a branch thereof, a hypoglossal nerve trunk, a lateralbranch of the hypoglossal nerve, a medial branch of the hypoglossalnerve, or suitable combinations thereof. A sensor can be placed on asensing target site comprising a trigeminal nerve or a branch thereof, afacial nerve or a branch thereof, a glossopharyngeal nerve or a branchthereof, a vagus nerve or a branch thereof, a hypoglossal nerve trunk, alateral branch of the hypoglossal nerve, a medial branch of thehypoglossal nerve, a tongue muscle, an upper airway muscle, a pharyngealmuscle, a cricopharyngeus muscle, or suitable combinations thereof. Themethod can further include activating the sensor to sense physiologicalsignals from the sensing target site and activating the stimulator tostimulate the stimulation target site based on the sensed physiologicalsignals to improve the patient's sleep disordered breathing.

Electrical Neuromodulation Device System

Referring to FIG. 1 , the system 10 can include an implantableneuromodulation device 20 and external controller 100. Controller 100can power neuromodulation device 20 through electromagnetic induction.Neuromodulation device 20 can include power receiver 30 with antenna 32.Electrical current can be induced in antenna 32 when it is positionedabove power mat 112 of controller 100, in an electric field produced bypower transmit antenna 112. Antennas 112 and 32 can also facilitatecommunication between controller 100 and neuromodulation device 20,respectively. This power/communication link between neuromodulationdevice 20 and controller 100 is shown generally by the arrow 70 in FIG.1 .

System 10 can also include a user interface 200 in the form of acomputer platform 202 running a custom application that enablescommunication with controller 100 wirelessly, as indicated generally byarrow 204. This can be done, for example, using Bluetooth or WiFi radiocommunication. In the example configuration of FIG. 1 , computerplatform 202 is a smartphone. The type of computer platform 202 could,however, vary. For example, the computer platform 202 can be a physicianor patient platform. Each platform 202 can have an application or “app”installed thereon that is user specific, i.e., a patient app or aphysician app. The physician platform would have the physician appinstalled, and the patient platform would have the patient appinstalled. The patient app can allow the patient to execute certaincommands necessary for controlling operation of neurostimulation device20, such as, for example, start/stop therapy, increase/decreasestimulation power or intensity, and select a stimulation program. Inaddition to the controls afforded the patient, the physician app canalso allow the physician to modify stimulation settings, such as pulsesettings (patterns, duration, waveforms, etc.), stimulation frequency,amplitude settings, and electrode configurations, closed-loop and openloop control settings and tuning parameters for the embedded softwarethat controls therapy delivery during use.

As indicated generally by arrow 206, computer platform 202 can beconnected (e.g., WiFi and/or LTE) to internet/cloud 208, whichfacilitates communication 214 with remote or cloud-based server 216.This can allow for the transfer of data between server 216 and computerplatform 202 via internet 208. Additionally, controller 100 itself canalso be internet connected (e.g., WiFi), as shown at 210. This can alsoallow for the transfer of data between controller 100 and server 216 viainternet 208.

System Communication

As shown in FIG. 1 and described above, system 10 can be configured toprovide various communication paths between the system components. Forexample, computer platform 202 being connected to controller 100 (see204) and to internet 208 (see 206) can facilitate a communication pathfrom remote server 216 (see 214) to neuromodulation device 20 itself(see 70). A communication path between server 216 and neuromodulationdevice 20 can also be established via WiFi link 210 of controller 100.

Additionally, recognizing that the physician may be remote from thepatient, a physician communication path can be established via theinternet connection 206 of the remotely located physician platform 202.Through this connection, remote physician platform 202 can communicatewith server 216 through internet connection 206. Remote physicianplatform 202 can also communicate with controller 100, either viainternet connection 210 (when enabled) or through patient controller202.

In addition to facilitating local control of system 10, e,g, controller100 and neuromodulation device 20, the various communication pathsdescribed above can also enable:

-   -   Distributing from server 216 software/firmware updates for the        computer platform 202, controller 100, and/or neuromodulation        device 20.    -   Downloading from server 216 therapy settings/parameters to be        implemented by computer platform 202, controller 100, and/or        neuromodulation device 20.    -   Facilitating therapy setting/parameter adjustments/algorithm        adjustments by a remotely located physician.    -   Uploading data recorded during therapy sessions.    -   Maintaining coherency in the settings/parameters by distributing        changes and adjustments throughout the system components.        System Operation Overview

The therapeutic approach implemented with system 10 can involveimplanting only neuromodulation device 20, leaving controller 100 as anexternal component to be used only during the application of therapy. Tofacilitate this, neuromodulation device 20 can be configured to bepowered by controller 100 through electromagnetic induction. Inoperation, power mat 110, operated by control unit 120, can bepositioned external to the patient in the vicinity of neuromodulationdevice 20 to position transmitting antenna 112 of the controller,located in the mat, close to receiving antenna 32 of the neuromodulationdevice. In the implementation where the system 10 is used to treat OSA,the power mat 110 can be positioned on or sufficiently near the sleepingsurface while the patient sleeps to maintain the position of thereceiving antenna 32 within the target volume of the electromagneticfield generated by the power antenna 112.

Through this approach, system 10 can deliver therapy to improve SDB suchas OSA, for example, by stimulating the HGN, for example, through ashorter, less invasive procedure. The elimination of an on-board,implanted power source in favor of an inductive power scheme caneliminate the need for batteries and the associated battery changes overthe patient's life.

Additionally, neuromodulation device 20 can implement electromyography(EMG) electrodes for sensing neuromuscular responses to physiologicalneeds of the patient during sleep. Such sensing electrodes cancontinuously monitor physiological intrinsic EMG signals from theanterior lingual musculature. For instance, EMG sensing electrodes canbe configured to detect neuromuscular responses from the genioglossusmuscle, which is innervated by the HGN or to detect neuromuscularresponses from other anterior lingual muscles and other muscles of thetongue.

Controller 100 can use transmitting antenna 112 for multiple purposes,for example: 1) to provide power to neuromodulation device 20 duringtherapy sessions, and 2) to communicate with the neuromodulation device.This communication can, for example, include programming, e.g.,uploading software/firmware revisions to neuromodulation device 20,changing/adjusting stimulation settings and/or parameters, and adjustingparameters of control algorithms. Controller 100 can receive theprogramming, software/firmware, and settings/parameters through any ofthe communication paths described above, e.g., from user interface 200or through direct WiFi internet connection, when available. Thecommunication paths can also be used to download data fromneuromodulation device 20, such as measured data regarding completedstimulation therapy sessions, to the controller 100. The controller 100can transmit the downloaded data to the user interface 200, which cansend/upload the data to server 216 via internet 208.

In operation, sensed EMG responses from the genioglossus muscle, forexample, can allow closed-loop operation of the neuromodulation device20 while eliminating the need for a chest lead. Operating inclosed-loop, the neuromodulation device 20 can maintain stimulationsynchronized with respiration, for example, while preserving the abilityto detect and account for momentary obstruction. The neuromodulationdevice 20 can also detect and respond to snoring, for example.

To facilitate real-time, closed-loop control, a control algorithm can beimplemented locally on neuromodulation device 20. This can be achieved,for example, by programming a control algorithm on anapplication-specific integrated circuit (ASIC) component ofneuromodulation device 20 (see below for the description of theneuromodulation device electronics).

Operating in real-time, neuromodulation device 20 can record datarelated to the stimulation session including, for example, stimulationsettings, EMG responses, respiration, sleep state including differentstages of REM and non-REM sleep, etc. For example, changes in phasic andtonic EMG activity of genioglossus muscle during inspiration can serveas a trigger for stimulation or changes in stimulation can be made basedon changes in phasic and tonic EMG activity of the genioglossus muscleduring inspiration or during different sleep stages. After the sleepsession, this recorded data can be uploaded to user interface 200 and toserver 216. Also, the patient can be queried to use the interface 200 tolog data regarding their perceived quality of sleep, which can also beuploaded to the server 216. Offline, the server 216 can execute asoftware application to evaluate the recorded data to determine whethersettings and control parameters can be adjusted to further optimize thestimulation therapy. The software application can, for example, includeartificial intelligence (AI) models that, learn from recorded therapysessions, how certain adjustments affect the therapeutic outcome for thepatient. In this manner, through AI learning, the model can providepatient-specific optimized therapy.

With reference to FIG. 9 , system 300 can be implemented within thesystem 10 and/or the neuromodulation device 20 to provide stimulation toimprove SDB according to open-loop control or closed-loop control. Thesystem can include one or more sensors 302 (which can be implantedand/or external), a computing device 304 (which can be implanted and/orexternal, and may be part of another device like the controller), andone or more electrodes 306 (which can be implanted and/or external). Theone or more sensors can be configured to record/detect physiologicaldata (e.g. data originating from the patient's body) over time includingchanges therein. Exemplary physiological data can include phasiccontraction of anterior lingual musculature, such as phasic genioglossusmuscle contraction, underlying tonic activity of anterior lingualmusculature, such as tonic activity of the genioglossus muscle, andcombinations thereof. Phasic contraction of the genioglossus muscle canbe indicative of inspiration, particularly the phasic activity that islayered within the underlying tonic tone of the genioglossus muscle.Changes in physiological data include changes in phasic contraction ofanterior lingual musculature, such as phasic genioglossus musclecontraction, changes in underlying tonic activity of anterior lingualmusculature, such as changes in tonic activity of the genioglossusmuscle, and combinations thereof. For example, EMG signal changes caninclude changes in the frequency, amplitude, spike rate, or otherfeatures within the EMG signal. In particular, changes in phasiccontraction of the genioglossus muscle can indicate a respiration orinspiration change and can be used to as a trigger for stimulation. Suchphysiological data and changes therein can be identified in recorded EMGsignals, such as during different phases of respiration includinginspiration. As such, one or more sensors 302 can include EMG sensors.The one or more sensors 302 can also include, for example, wireless ortethered sensors that measure, body temperature, movement, breath sounds(e.g. audio sensors), heart rate, pulse oximetry, eye motion, etc.

The computing device 304 can be configured to provide open-loop controland/or closed-loop stimulation to configure parameters for astimulation. In other words, with respect to closed-loop stimulation,the computing device can be configured to track the patient'srespiration (such as each breath of the patient) and stimulation can beapplied during inspiration, for example. However, with respect toopen-loop stimulation, stimulation can be applying without trackingspecific physiological data, such as respiration or inspiration.However, even under such an “open loop” scenario, the computing devicecan still adjust stimulation and record data, to act on suchinformation. For example, one way the computing device can act upon suchinformation is that the computing device can configure parameters forstimulation to apply stimulation in an open loop fashion but can monitorthe patient's respiration to know when to revert to applying stimulationon a breath to breath, close-loop fashion such that the system is alwaysworking in a close looped algorithm to assess data. Accordingly,adjustments to stimulation may be based on an input to the computingdevice 304, which may be based on one or more trends in physiologicaldata recorded by the one or more sensors 302 over time. Treatmentparameters of the system may be automatically adjusted in response tothe physiological data. The physiological data can be stored over timeand examined to change the treatment parameters; for example, thetreatment data can be examined in real time to make a real time changeto the treatment parameters.

An example of the computing device 304 programmed to implement theclosed-loop scenario is shown in FIG. 10 . The computing device 304 caninclude a memory 422 (e.g., a non-transitory memory), a processor 424(e.g., an integrated circuit, such as an application specific integratedcircuit (ASIC)), or an ASIC comprising both a memory and a processor.For example, the memory 422 can be a computer-usable orcomputer-readable medium that can contain or store the machine-readableinstructions (which are, for example, a program) for use by or inconnection with the instruction or execution of a system, apparatus ordevice (like the computing device 304) by the processor 424. Thecomputer-usable or computer-readable medium can be, for example but notlimited to, random access memory (RAM) including static or dynamic RAM,read-only memory (ROM), flash memory, an Erasable Programmable Read OnlyMemory (EPROM), floating point memory, or combination thereof includingcombinations thereof on the same ASIC. The processor 424, for example,can include one or more processing cores, processing units, or the like.The memory 422 can store machine readable instructions, while theprocessor 424 can access the memory 422 and execute the machine readableinstructions (e.g., which can include one or more programs) and causethe computing device 304 to perform operations of a monitoring component426, an identification component 427, and/or a classification component428. The processor 424 can interpret the physiological informationcoming from the sensors, including decoding data, analyzing data,recognizing patterns, etc.

The monitoring component 426 can monitor the physiological data recordedby the sensor(s) 302. The identification component 427 can identify atrigger within the physiological data (e.g., related to respiration).For example, the monitoring component can monitor EMG waveformcharacteristics like spike rate, amplitude, and frequency, as well asphasic activity and tonic activity (again monitoring for changes inamplitude, frequency or other parameters of the EMG). The identificationcomponent can identify the trigger during such monitoring (e.g. acharacteristic change in the EMG waveform). In one example, the triggercan be an associated change in the EMG, such as short term contractionof the genioglossus muscle indicating phasic genioglossus muscleactivity or longer term changes in genioglossus muscle activityindicating a change in underlying tonic tone of the genioglossus muscleseen over one or more parts or repetitions of the physiological data.The trigger can be identified as a biomarker for a condition related tosleep, such as a change in at least one parameter physiological data. Insome instances, the biomarker can be inspiration. In other instances,the biomarker can be a body position. In other instances, the biomarkercan be a stage in a sleep cycle (e.g., awake, non-REM sleep—stage 1light sleep, stage 2 light sleep, stage 3 deep sleep, REM sleep, etc.).In some instances, motion detection and/or other biomarkers can be usedto automatically turn the therapy on only once the patient has fallenasleep and to determine the parameters of stimulation to optimallymaintain airway patency throughout the night (including adaptingstimulation based on sleep stage and body position) without causingunnecessary discomfort or leading to arousal events to increase patientcomfort and adherence to therapy. Stimulation can be ramped up as thepatient moves from light to deep sleep or ramped during each stimulationphase such that the first pulse in a pulse train has less amplitudeand/or pulse width than the last pulse in the pulse train. In someinstances, stimulation will automatically shut off if the patient wakesup and re-initiate as they fall back to sleep.

The awake stage of the sleep cycle refers to a relaxation stage when thesubject is first lying in bed or lying in bed trying to fall asleepagain. Non-REM sleep has three stages and is a stage of sleep withoutrapid eye movement. The REM stage includes REM sleep, where eyes moverapidly from side to side behind closed eyelids, breathing becomesfaster and irregular, heart rate and blood pressure increase to nearwaking levels, and arm and leg muscles become temporarily paralyzed.

Non-REM stage 1 refers to the changeover from wakefulness to sleep(lasting several minutes). During non-REM stage 1, a subject'sheartbeat, breathing, and eye movements slow and muscles relax withoccasional twitches. Non-REM stage 2, the longest of all the stages, isa period of light sleep before entering deeper sleep, where heartbeatand breathing slow, muscles relax even further, body temperature dropsand eye movement stops. Non-REM stage 3 refers to the period of deepsleep needed to feel refreshed in the morning, where heartbeat andbreathing slow to their lowest levels during sleep, muscles are relaxed,and it may be difficult to awaken.

The sleep state can be determined, for example, based on information inthe physiological data (e.g., tonic genioglossus muscle activity asindicated on an EMG). Once the sleep state is recognized, the goal is toapply therapy in such a way to minimize patient discomfort and to alsominimize potential stimulation related arousal events. This may include,reducing the amplitude of stimulation during stage 1 and stage 2 sleep,and increase amplitude during stage 3 and REM. This may also includeramping therapy over a longer period of time, meaning from zero toprogrammed output over a longer time period, during stage 1 and 2 sleepvs. stage 3 and REM sleep or ramping therapy within each pulse train,when applied during inspiration for example.

For example, if certain EMG activity is detected, like phasic changes inEMG activity that is indicative of inspiration during any phase ofsleep, the system may deliver stimulation during the respiratory periodof inspiration. The system can apply stimulation to the hypoglossalnerve, for example, using a particular set of electrodes, waveform,pulse width, frequency, intra-pulse interval and pulse ramp rate thatprovide therapeutic airway patency during inspiration. The system canstop stimulation during the exhalation period and can continue tomonitor the physiological EMG, from the genioglossus muscle for example,throughout the inspiratory and exhalation periods of each breath. Thesystem can adjust the stimulation parameters and/or the electrodesselected for stimulation as necessary to optimize the stimulation toprovide the optimal airway patency, based on additional biomarkersincluding, sleep state, body position, or the like. The closed loopalgorithms embedded within the neuromodulation device or neuromodulationlead can continuously monitor and adjust therapy based on thephysiological data and triggers and use rule based classification todetermine when, how and for what period of time, to apply and adjuststimulation to provide optimal airway patency during sleep.

For example, if certain EMG activity, like tonic and phasic EMG activitydrops or ceases during REM, the system may deliver a stimulationperiodically based on predetermined physician programmed parameters, thesystem may rely on previous known patient specific parameters to applystimulation, or the system may use a default periodic stimulation thatis applied throughout REM sleep. The system can also monitor EMG throughthe REM period to determine when to stop using the periodic stimulationand when to re-initiate applying stimulation during each inspiratoryevent.

In some instances, the system may not turn on stimulation immediatelywhen the neuromodulation device is within the field from the transmitcoil. In this case, the system can turn on and monitor an EMG signal,e.g., detecting tonic and phasic muscle activity, to understand thesleep stage. Once the system has determined the patient is sleeping,entering stage 1 of sleep or stage 2 of sleep, the system 10 can startto provide therapy in a physiological manner, e.g., starting to applysmall amount of stimulation using a stimulus ramp during eachstimulation period, such that unnecessary arousal events or discomfortis not caused during initial phases of sleep. In this configuration, theEMG may be monitored for several minutes or several hours to determinethe state before the system initiates therapy. Many individuals with OSAalso suffer from insomnia, in which the individual has trouble fallingasleep, and in this case, a negative feedback loop can cause the patientadditional anxiety, such that they are fearful that the therapy willturn on prior to when they fall asleep and as such are not relaxedenough to fall asleep. This can cause the individual to turn offtherapy, or over time discontinue use of the therapy. A “smart” systemthat is able to recognize when patients are asleep and apply therapysuch that it is physiological will increase therapy adherence andefficacy. Once the system recognizes non-REM stage 1, for example, thesystem can start to recognize non-REM stage 2, non-REM stage 3, REMsleep, or the like.

For example, the ASIC (an example of processor 424) can be configured tocontrol a custom algorithm, which can control the therapy application.For example, the ASIC can be configured to run embedded digital logicthat uses information gathered by an EMG sensor to decide when, for howlong, and at what stimulation parameters to stimulate to provide theoptimal therapy to the subject to control the volume of air capable offlowing through the upper airway, also known as airway patency. Theembedded digital logic can sense EMG activity, which can be known to thealgorithm to correspond with respiration, more specifically toinspiration and exhalation. The algorithm can decode the EMG activity totrigger stimulation of the anterior musculature and/or the hypoglossalnerve (including distal branches thereof) bilaterally, for example, toopen the airway, such that the therapy is linked to each respiration,each inspiration and each exhalation, for example. Therapy can thus beprovided during each breath, specifically during inspiration, forexample, all by using embedded correlative knowledge of the EMG featuresthat correspond to respiration. The embedded logic can include knowledgeof EMG features that are specific to body position, chin position, sleepstate (e.g. REM, non-REM), movement, and other physiological parametersthat can elucidate and optimize therapy. The algorithm can use adaptivelearning to learn individual subject specific EMG features thatcorrelate to the above physiological states during sleep to provideadditional optimization that is subject specific. The adaptive learningcan be done manually with physician input or may be done completelywithin the algorithm based on pre-determined limits and knowledge or canbe done with the cloud database and the additional adaptive learningthat the cloud software can use to analyze the data from each patientand each sleep session. The algorithm, while still based on respiratoryinformation sensed through the EMG sensor, can also have differentmodes. In one mode, the algorithm can be running and can provide therapybreath to breath, specifically during inspiration; in another mode, thealgorithm can be learning, looking for inputs from the EMG and also fromthe user (e.g. patient, physician, etc.); in another mode, the algorithmcan provide more continuous control of the airway, providing periodicstimulation that can be sustained for periods of time. In another mode,the algorithm can be sensing EMG information, but not providing therapybreath to breath, instead waiting until a forthcoming collapse of theairway has been identified and reacting by providing therapy thatprevents the collapse from occurring. The EMG information can include,the amplitude of the EMG, the frequency components of the EMG, spikesensing, envelope sensing, and other features that can be taken directlyfrom the EMG signal to control the algorithm and provide biomarkers forrespiration and for collapse of the airway. It is understood, that thealgorithm may use any or all of these features throughout the sleepperiod and can switch between modes based on the EMG activity as sensedby the EMG sensor or the system may be hard programmed to only run onealgorithm.

The system can apply therapy in a manner that is not causing discomfortand/or arousal events in the patient. As the patient moves through thestages over the course of the entire night, the system can continuouslyadapt to the sleep stage (and/or patient need). For example, the largestneed for stimulation can be during deep sleep (non-REM stage 3) and REM,where discomfort and arousal are unlikely, so the system can apply morestimulation, since arousal and discomfort are unlikely during thesestages. The amount of time the patient is spending in each stage ofsleep can also be tracked, which is very useful for tracking outcomes,as most OSA patient do not enter into deep sleep often due to arousals.

The classification component 428 can apply a rule-based classificationto the trigger to determine whether one or more stimulation parametersapplied by one or more of the stimulating electrodes should be alteredbased on a biomarker related to sleep. As stated above, biomarkersinclude respiration phase (such as inspiration including periods withininspiration), sleep stage during one or more sleep cycles, and/or bodyposition during sleep as indicated by an EMG or other sensor or sensedactivity. Stimulation parameters, as stated above, include, for example,pulse width, amplitude, frequency, waveform shape, electrodeposition/configuration, or the like). Initial rules of the rule-basedclassification used by the algorithm can be set for the patient and/orset based on historical values for a population, historical values for apatient, and/or patient derived values. Subsequent rules of thealgorithm can be learned and/or updated and/or personalized based on anartificial intelligence learning process.

Feedback related to the stimulation (e.g., after it is delivered) can begiven to the computing device 304. The computing device 304 can receivethe feedback and may change one or more stimulation parameters.

An example closed-loop control scenario involves the one or more sensors302 (implanted adjacent to an anterior lingual muscle, such as thegenioglossus muscle) that can detect/record physiological data overtime. The physiological data can include EMG data from the musculatureof the anterior airway, which can include characteristic signals thatcorrelate to respiration, but also can correlate to sleep position,sleep state, and/or other physiological characteristics important forthe treatment of SDB. The computing device 304 can monitor thephysiological data recorded by the one or more sensors 302 to identify atrigger within the physiological data. The trigger can be identified asa biomarker for a condition related to sleep (e.g., inspiration). Arule-based classification can be applied to the trigger to determinewhether one or more parameters of the stimulation (e.g., delivered byone or more electrodes 306 or electrode contacts to the hypoglossalnerves or other nerves) should be altered based on the biomarker.

Changes in voltages on the transmit receptor can be sensed, as well ason the power receiver and resulting changes in impedances to determinethe position and movement of the power receptor within the magneticfield. In this aspect, the changes in voltage and impedance between thetwo coils of the power antenna can provide additional information to thesystem to inform the close loop algorithm and to inform additionalrefinement to the therapy. This type of position sensor may haveadditional usages beyond therapy optimization as it may provideadditional data about sleep quality over time, as well as health relatedinformation. In addition, the impedance data between the coils can becorrelated with activity, which can be used to also track wake vs. sleepcycles. These data along with EMG data, e.g. tonic EMG activity from thegenioglossus muscle, can be used together to understand and learn wakevs. sleep throughout the period spent attempting to sleep (e.g., whenthe power receive coil is within the inductive field volume of thetransmit coil).

Several wired or wireless input applications, including smart phone ortablet applications can also be used, wireless remote controls forexample. These additional input applications can provide additionalinputs to the system to adjust the therapy, adjust the closed loopalgorithm, adjust stimulation outputs, adjust optimization or to adjustthe algorithm mode as necessary. The input application can displayelectromyogram data for the user, allows the user to adjust theparameters that control the EMG collection, such as the input filters,trigger amplitudes, frequency ranges, etc.

An input application can also allow for automated therapy titration. Inthis mode, the application can run custom software that providesstimulation to a target site of the subject, such as a target nerve ortarget muscle and monitors the resulting evoked EMG activity of amuscle, such as an anterior lingual muscle, including the genioglossusmuscle. The resulting EMG activity can correlate to the amount of airwayopening desired (as inputted into the application) and thus can allowfor automated therapeutic stimulation parameter settings and eliminatetime consuming parameter adjustments during sleep Non-limiting exampleof stimulation parameter settings include stimulation pulse width,amplitude, frequency, electrode position/configuration and the like. Inthis aspect, the system can determine the therapeutic stimulationoutputs and allows the subject/physician to fine tune as necessary. Thesubject or physician can rerun the automated parameter adjustmentapplication at any time, and through the applications can be monitoredremotely so that titration, programming can be done from the comfort ofthe subject's home.

The resultant evoked EMG signal can be continuously monitored andstimulation parameters needed to produce the required tongue motion foreffective treatment can be determined, even if the response to a givenset of stimulation parameters changes over time, effectively reducingthe amount of testing required for initial programming as well as theneed for ongoing follow-up testing. Also, issues with the therapy (e.g.,stimulation according to certain stimulation parameter settings is notproviding the tongue movement necessary to open the airway) can beidentified and alerts can be generated for the patient and/or physician(this allows for quicker response and proactive management of thesystem).

Another aspect of the present disclosure can include a method 700 (FIG.11 ) for providing neural and/or muscular stimulation according to aclosed loop algorithm to treat SDB. The method 700 can be executed bycomponents of the systems as described and shown in the figures, forexample. Portions of the method 700 can be stored at least in part on anon-transitory memory and executed by a processor.

For purposes of simplicity, the method 700 is shown and described asbeing executed serially; however, it is to be understood and appreciatedthat the present disclosure is not limited by the illustrated order assome steps could occur in different orders and/or concurrently withother steps shown and described herein. Moreover, not all illustratedaspects may be required to implement the method 700 and/or more than theillustrated aspects may be required to implement the method 700.Additionally, one or more aspects of the method 700 can be stored in oneor more non-transitory memory devices and executed by one or morehardware processors.

At 752, physiological data (e.g., related to inspiration, sleep stageand/or body position as indicated by an EMG, for example) recorded byone or more sensors can be monitored. The one or more sensors can beimplanted adjacent to the anterior lingual muscle, such as thegenioglossus muscle, or in the plane between the genioglossus muscle andgeniohyoid muscle, for example. At 754, a trigger can be identifiedwithin the physiological data. The trigger be a change in at least oneparameter of the physiological data (e.g., indicative of inspirationduring respiration, body position, and/or a stage in the sleep cycle asindicated by an EMG, for example).

At 756, a rule-based classification can be applied to the trigger todetermine whether one or more parameters of the stimulation should bealtered based on a biomarker represented by the trigger. A signalcomprising configuration/setting information for the parameters can besent to one or more electrodes located adjacent to the hypoglossalnerve, for example. The stimulation parameter(s) can be titrated andadapted based on the trigger to optimize airway muscle tone.

Neuromodulation Device Configuration

The neuromodulation device can have a variety of configurations, whichcan be tailored to the specific therapy being applied and/or to theanatomy at the site at which the stimulation therapy is applied. Anexample configuration of a neuromodulation device 20 is illustrated inFIG. 2 . Neuromodulation device 20 can include a first stimulation lead21A and a second stimulation lead 21B, each comprising a lead body 23having a nerve cuff electrode 25 located thereon. The nerve cuffelectrode 25 (enlarged in both FIGS. 1 and 2 for clarity) can comprise acuff body 27 comprising a stimulating electrical contact 29 disposedthereon configured to deliver a stimulation signal to a target site.Although neuromodulation device 20 is illustrated as including twostimulation leads for stimulation of the left and the right hypoglossalnerve, for example, the neuromodulation device can include only onestimulation lead or more than two stimulation leads. Stimulating lead 21can be generally elongated and include a plurality of electrodes 29spaced along its length. The lead body can have different shapes. Forexample, the lead body can be cylindrical, flat or have an ovalcross-sectional shape. The lead body can also have enlarged segments toallow for disposition of larger electrode pads or contacts thereon alongthe length of the lead body.

The stimulation leads as well as the nerve cuff electrodes can beconfigured to stimulate nerves bilaterally or unilaterally. Thestimulation leads and nerve cuff electrodes can be configured tostimulate various combinations of nerves and nerve branches. Such nervesand nerve branches include the HGN (including a HGN nerve trunk, amedial branch of the HGN, a lateral branch of the HGN (as described inmore detail below)); a glossopharyngeal nerve or other nerves thatinnervate a pharyngeal muscle; a lingual nerve; other nerves thatinnervate anterior lingual muscles; and/or other nerves that innervatethe tongue.

The tongue receives afferent (sensory) innervation from branchesemanating from four cranial nerves: a) trigeminal nerve, mainly themandibular and lingual nerves, b) facial nerve, mainly the chordatympani nerve, c) glossopharyngeal nerve and d) vagus nerve, mainly thesuperior laryngeal nerve. The efferent (motor) innervation of the tongueemanates from the hypoglossal nerve with small contribution form thecervical vagus nerve. The upper esophageal sphincter (otherwise calledthe cricopharyngeus muscle) has motor control through theglossopharyngeal nerve as well. Finally, innervation to the larynxoriginates from branches of the vagus nerve, the superior laryngealnerve and recurrent laryngeal nerve.

The stimulation lead, which can be configured in many shapes,orientation and include one or more electrodes as needed to provideimproved therapy, can be configured to stimulate any of these nervesand/or muscles bilaterally or unilaterally. The sensing lead can beconfigured to sense from different lingual muscles as to adopt a closeloop control for therapy.

Further, although the second stimulating lead 21B is illustrated ashaving three stimulating electrical contacts 29 b and first stimulatinglead 21A is illustrated as having four stimulating electrical contacts29 a, the stimulating leads can have more or less stimulating electricalcontacts. Each electrode 29 can be configured and utilized independentlyof the other electrodes. Because of this, all or some of electrodes 29,whichever is determined to be most effective for a particularimplementation, can be utilized during the application of stimulationtherapy.

Further, although FIG. 2 illustrates only one nerve cuff electrodelocated on the stimulating leads, the lead(s) can comprise more than onenerve cuff electrode. Referring to FIG. 3 , a stimulating lead 53 cancomprise a plurality of nerve cuff electrodes. For example, FIG. 3(which mainly illustrates the nerve cuff electrodes of the lead) depictsstimulating lead 53 having a proximal cuff electrode 33 comprising acuff body 51 having a stimulating electrical contact 37 disposedthereon. Proximal nerve cuff electrode 33 is sized and dimensioned to atleast partially wrap around the circumference of a hypoglossal nervetrunk at or proximal to a branch point between a medial branch and alateral branch of a hypoglossal nerve that innervates the genioglossusmuscle. Stimulation lead 53 also includes a medial cuff electrode 39comprising a cuff body 41 comprising a stimulating electrical contact 43disposed thereon. Medial cuff electrode 39 is sized and dimensioned toat least partially wrap around the circumference of a medial branch ofthe hypoglossal nerve at or proximate to the branch point between themedial branch and the lateral branch of the hypoglossal nerve thatinnervates the genioglossus muscle. Stimulation lead 53 further includesa lateral cuff electrode 45 comprising a cuff body 47 comprising astimulating electrode contact 49 disposed thereon. Lateral cuffelectrode 45 is sized and dimensioned to at least partially wrap aroundthe circumference of a lateral branch of the hypoglossal nerve at orproximate to the branch point between the medial branch and the lateralbranch of the hypoglossal nerve that innervates the genioglossus muscle.The branch point referred to above is distal to the branch of thehypoglossal nerve that innervates the styloglossus and hyoglossus muscleand proximal to the distal most fibers of the hypoglossal nerve. Themedial cuff electrode and the lateral cuff electrode can be sized anddimensioned to at least partially wrap around the circumference of themedial branch and the lateral branch of the hypoglossal nerverespectively at a location distal to the proximal cuff electrode.Although the proximal, medial and lateral nerve cuff electrodes areillustrates as being separate cuff electrodes, they can be an integralone-piece nerve cuff electrode. The nerve cuff electrode cancollectively have a Y-shape. Each of the nerve cuff electrodes cancomprise one to two stimulating electrical contacts, although they canalso include more than two stimulating electrical contacts. In certainaspects, one or more of the nerve cuff electrodes comprises a pluralityof electrodes arranged circumferentially about the respective cuff bodyspaced approximately 90 degrees apart. The stimulating electricalcontacts can have various configurations such as a half-moonconfiguration arranged circumferentially about the respective cuff body.Again, as mentioned above, the nerve cuff electrodes can be configuredto stimulate the hypoglossal nerve trunk, the lateral branch of thehypoglossal nerve, and/or the medial branch of the hypoglossal nerveeither individually or in various combinations including in combinationwith stimulation of the glossopharyngeal nerve and/or lingual nerve.

It is well known in the art that one limitation of using cuff electrodesis the ability to selectively stimulation specific nerve fibers thatproduce the neurological function of interest when using a nerve cuffelectrode on the main nerve trunk. This limitation can limit therapy andoutcomes due to unwanted stimulation that causes side effects anddiscomfort. Therefore, applying stimulation via a nerve cuff on the maintrunk of a nerve causes limitation in the therapy, however, using nervecuff electrodes have advantages when placed on the right nerve or nervebranch to produce the stimulation of interest while minimizing sideeffects. Nerve cuff electrodes can reduce electrical current spread tostructures outsides the nerve cuff, hence reducing side effects. Placingone or more nerve cuffs at specific nerve branches can provide directstimulation to the nerve fibers of interest and allow for tailoring ofthe therapy by stimulating one or more nerve branches to produceimproved stimulation for therapeutic outcomes that are meaningful topatients. The stimulation can be tailored by using specific levels ofcurrent at each of the one or more cuff electrodes on the nerve branchesto cause the right outcomes for each patient. The nerve branchingpatterns can and are different patient to patient and hence the need toprovide one or more cuff electrodes placed on specific branches and thesystem flexibility to provide specific amount of current to each cuff isadvantageous to cause specific actions without unwanted side effects.Each of the one or more cuff electrodes, can have one or more electrodesthat are sized, shaped and orientated to address the specific fiberswithin the nerve branch of interest and to stimulate those specificfibers for therapeutic outcomes. The electrodes within each cuff may notall be the same and can have different shapes and sizes to providespecific stimulation to each nerve branch. The size of the nerve branchand the types of fibers within the nerve branch can be important to theunderstanding of the stimulation and electrode configurations.

A neuromodulation lead can also include a sensing lead 81 comprising alead body 83 having a sensor disposed thereon. The sensor is configuredto record physiological data and can be, for example, an EMG electrode.FIG. 5 illustrates one 3-D shape to which a sensing lead 81 (as well asa stimulation lead) can be formed. The example configuration of FIG. 5shows the sensing lead formed three-dimensionally in a generallyomega-shape, as shown in the plan view of FIG. 5 . This particular 3-Dconfiguration can be implemented to position the sensing electricalcontacts at different positions along the HGN and genioglossus muscle,where the neuromodulation device is configured to treat SDB, such asOSA, for example. More specifically, the configuration of the sensinglead in FIG. 5 can allow for the right and left electrical contacts (asviewed in FIG. 5 ) to be placed in very close proximity to the HGNbranches and to provide slight cranial pressure to place the electrodesonto the surface of the genioglossus muscle, the largest of the tongueprotrusion muscles. The right and left electrical contacts in animplanted configuration can extend along the posterior-anterior courseof the HGN, placing the electrical contacts at or near the location ofthe branch points, such as distal branch points from the main trunk.Electromyography recording of the genioglossus muscle have shown thatthat the activity is more pronounced as the recordings progress to amore anterior positions on the genioglossus. By using this specificshape, the EMG recording using one or more electrodes can be modified asneeded and moved to a more anterior location as needed to produce thebest electrical signal characteristics. In addition, the electrodesconfiguration used for recording can be modified to capture unilateralEMG (one from both sides of the patient) which can be used to sensedifferences between the right and left side (or vice versa) duringtherapy or to naturally occurring differences that occur duringdifferent sleeping positions, which could be used by the system todirect therapy. Using this specific shape, that tracks the nervebranching patterns bilaterally and by applying an slight upward bias toeach of the sections that house the electrodes allows for reduced signalto noise ratio in the recordings, reducing movement during use, andprovides for stable recording over the duration of the implant.

In more detail, the sensing lead can be inserted and positioned in theplane between the geniohyoid muscle and the genioglossus muscle. Thesensing lead can be configured to position sensing electrical contactsalong the nerve distribution of the hypoglossal nerve and its branchesbilaterally and configured to sense electrical information from thegenioglossus muscle by applying a slight upward pressure against thedorsal surface of the genioglossus muscle with the 3D bias of thesensing lead when the electrode are placed. As depicted in FIG. 5 , inan aspect, sensing lead 81 can comprise a lead body 83 having a leftportion 55 comprising a left set of electrical contacts 57, a rightportion 59 comprising a right set of electrical contacts 61, and anintermediate portion 63 therebetween defining an apex 65 of lead body53. As described in more detail below, the sensing electrical contactscan be used to sense electrical activity, such as intrinsic or evokedelectrical signals. FIG. 5 depicts two electrical contacts per side butthe sensing lead can comprise more or less sensing electrical contacts.For example, the left and right portion of the lead body can each haveone electrical contact and a common reference electrical contact can belocated in the intermediate portion of the lead body for example.

Lead body 83 can be biased towards a substantially omega shape, moregenerally speaking a shape that allows for the two sections to extendfrom a center section, when fully deployed as shown in FIG. 5 . In otherwords, lead body can be configured to transition from a substantiallylinear shape, in a non-deployed state, such as during insertion, to asubstantially omega shape, as shown in FIG. 5 , when fully deployed.When the sensing lead is in a non-deployed state, sensing electrodes 57and 61 can be arranged in two groups of two electrical contacts spacedalong the distal portion of lead body 83. One group of electricalcontacts 61 a and 61 b can be positioned distally near an end of leadbody 53 and one group 57 a and 57 b can be positioned proximally,between the distal group and electronics package (not shown in FIG. 5but illustrated in FIG. 2 ). The configuration of electrical contacts 57and 61 can, however, vary. The sensing lead can include a differentnumber of electrical contacts, and/or the electrical contacts can begrouped, spaced, or otherwise arranged in different configurations alongthe length of the lead.

The sensing lead is fully deployed when the neuromodulation lead isimplanted in the patient's body and the electrical contacts arepositioned at the desired locations in the patient's body. The omegashape of the sensing lead can be created at the time of manufacturingsuch that the final form of the lead body is biased to have the omegashape, such bias being overcome if needed during insertion of the lead.The bias can be created, for example, by heat shaping or materialshaping or other methods of manufacturing a biased lead.

The sensing electrical contacts can be ring electrical contactsextending substantially 360° about the lead body, for example, and canhave substantially the same size as the target stimulation site(s). Thesensing electrical contacts can also be directional electrodes and notextend 360° about the lead body. Further, the electrical contacts canhave coatings to reduce the signal to noise ratio and/or allow forbetter long-term recording characteristics.

Intermediate portion 63 of lead body 83 can define an apex 65 and anultrasound marker 67 can be disposed at apex 65. As such, the sensinglead can be inserted via ultrasound and ultrasound marker 67 can allowthe user to identify when the apex of the sensing lead is positioned atmidline, allowing the electrical contact sets 57 and 61 to be positionedalong the distribution of the hypoglossal nerve and its branchesbilaterally. Ultrasound can also be used to track motion or potentialdislodgment of the lead over time. One or more anchors can be disposedon the lead body to secure the sensing lead in place. Such anchors canbe hard or soft anchors, for example, including tines, barbs,prefabricated sutures, deployable anchors including time dependentdeployable anchors (e.g. anchors that are polymer coated and deploy orrelease once the polymer dissolves), or combinations thereof.

In certain aspects and with respect to FIG. 6 , when sensing lead 69 (aswell as a stimulation lead) is fully deployed, intermediate portion 71of lead body 73 defining apex 75 can be located inferior/caudal/lower tothe left and right electrode sets 77 and 79 respectively. This can beseen in the inferior bend or bias of lead body 73 that leads intointermediate portion 71. Such a bend or bias can allow the lead to exertupward/superior/cranial pressure to press the sensing electrodes againstthe genioglossal muscle and/or the hypoglossal nerve to allow for bettercontact between the electrode sets and the hypoglossal nerve and/orgenioglossus muscle. In particular, this pressure is created by theintermediate portion, including the apex, being more caudal in the bodyand allowing the left and right portion of the lead body to be pushedmore cranially into the genioglossus muscle. This bias allows for bettercontact with the genioglossus muscle, more lead stability and hencebetter long-term performance of the lead and allowing for a bettersignal to noise ratio for recording purposes.

In particular, such a bias can reduce motion of the lead afterencapsulation/scar tissue grows around the lead and thus allow forbetter contact between sensing electrodes and the muscle(s) from whichelectrical activity is sensed. The inferior bias can also reduce theamount of encapsulating tissue around the lead as well. This can improvethe recording of electromyography (EMG) signals from muscles innervatedby the hypoglossal nerve since the more encapsulating tissue around thesensing electrodes, the harder it can be to detect an EMG signal longterm. As such, reduced motion of the lead and less encapsulation oftissue around the lead can result in better EMG recording.

Referring back to FIG. 2 , neuromodulation device 20 can include powerreceiver 30 and electronics package 50. Power receiver 30 can include acoiled receiver antenna 32 that is packaged in a protectivebiocompatible material and is operatively connected to the electronicspackage 50 and electronic components 52 mounted therein. The stimulatingand sensing leads 21 and 31 can be operatively connected to theelectronics package 50, which controls the operation of the stimulatingelectrical contacts 29 and sensing electrical contacts 35. Electricalcontacts 29 and 35 can be electrically connected to electronics package50 by conductors, such as wires. As stated above, electrical contacts 29can be utilized as stimulating electrodes to apply stimulation to atarget anatomical structure, such as, for example, a nerve or muscle.Sensing electrodes 35 can be used to detect and measure an EMG response,for example, from a neuromuscular structure associated with the targetnerve. For a SDB treatment implementation illustrated in thisdescription, the target nerve can be the HGN and the associated musclecan be the genioglossus muscle. The neuromodulation device can, however,be used to target other nerves and to measure physiological electricalsignals from other anatomical structures, such as EMG responses, fromother neuromuscular structures.

Electronic components 52 are preferably implemented in anapplication-specific integrated circuit (ASIC). The electroniccomponents 52 can, however, include one or more ASICs, discreteelectronic components, and electrical connectors for connecting theelectronic components to power receiver 30 and/or leads 21 and 31. Theelectronic components, whether embodied in a single ASIC or one or morecomponents, can, for example, include processing and memory components,e.g., microcomputers or computers-on-a-chip, charge storage devices(e.g., capacitors) for accumulating a charge and supplying stimulationpower, and solid state switching devices for selecting the identities ofthe electrodes (e.g., anode, cathode, recording electrode) andmodulating power supplied to the electrodes (e.g., pulse-widthmodulation (PWM) switches).

To provide comfort to the patient and ease of insertion for physicians,the neuromodulation device 20 can have a generally soft/flexibleconstruction. This soft/flexible construction can apply to leads 21 and31, power receiver 30, or both the leads and the power receiver. In oneexample configuration, the neuromodulation device components—powerreceiver 30, electronics package 50, and leads 21 and 31—can be coatedor otherwise encased simultaneously in a single operation, such as aninsert molding with a biocompatible material, such as silicone, epoxy,and various suitable polymers.

The power receiver and the leads can have a flexible configuration thatallows either or both structures to bend or flex, which facilitatesimplantation compatibility with a variety of anatomical structures. Thepower receiver can be generally flat and planar in configuration and thestimulation and sensing leads can be generally elongated inconfiguration in a non-deployed configuration and can extend axiallyfrom the electronics package. To facilitate the flexible configurationof the leads, the stimulating and sensing electrical contacts and theconductors that connect the sensing and stimulating electrical contactsto the electronics package can be encased and supported in a covering.The covering can be formed of a biocompatible material, such as siliconeand various suitable polymers, and can be configured to leave exposedthe stimulating and sensing electrical contacts or portions thereof. Thecovering can be formed, for example, in the aforementioned insert moldedcovering of the neuromodulation device.

To facilitate the flexible configuration of power receiver 30, antenna32 can be formed on a soft substrate so as to be flexible and conform tothe anatomy at the site of implantation. For example, power receiver 30can have a flexible printed circuit board (PCB) construction in whichantenna 32 is etched from a thin layer of conductive metal laminated ona substrate 38 (see FIG. 4 ) constructed of a flexible material, such asa polymer. In one particular flexible PCB construction, the substratecan be a polyimide material and the conductive metal can be copper.Other flexible PCB constructions can be implemented. Antenna 32 can beencased and supported in covering 48. Covering 48 can be formed of abiocompatible material, such as silicone, epoxy and various suitablepolymers. Covering 48 can be formed, for example, in the aforementionedinsert molded covering of the entire neuromodulation device 20structure.

The flexible PCB of power receiver 30 can extend into electronicspackage 50 and can be configured to mount the electronic components 52.The PCB can also be configured to interface conductors of the leads,and/or to form portions of the lead itself. In this instance, powerreceiver 30, electronics package 50, and leads 21 and 31 (or portionsthereof) can be encased in the biocompatible material (e.g., silicone,epoxy and various suitable polymers) simultaneously.

The power receiver is designed with the goal of delivering maximum powerto the neuromodulation device from a given external magnetic field. Withthis goal in mind, for the HGN stimulation implementation of the exampleconfiguration disclosed herein, power receiver 30 and receiving antenna32 have a unique configuration designed to adhere to several criteriafor neuromodulation device 20. The criteria depend, of course, on theintended therapeutic use of the system and the configuration resultingtherefrom. The criteria set forth below are specific to an exampleconfiguration of system 10 for treating SDB including OSA vianeuromodulation of the HGN:

-   -   The neuromodulation device 20 operates within the guidelines for        maximum permissible magnetic field exposure as recommended in        IEEE Standard C95.1-2005 (Reference 3).    -   The receiving antenna 32 allows for near continuous power        consumption (10-30 milliwatts (mW)) from the neuromodulation        device 20.    -   The receiving antenna operates at a frequency ranging from 100        kHz to 2.4 GHz ISM (industrial, scientific, medical band of the        radiofrequency spectrum). In one particular implementation,        frequencies of 6.78 MHz or 13.56 MHz were used.    -   The receiving antenna 32 has a diameter of 2-3 cm. and be as        thin as possible to maintain flexibility.    -   The neuromodulation device 20 is small enough for minimally        invasive subcutaneous implantation within the soft tissue of the        sub-maxillary neck.    -   The neuromodulation device 20 maintains a soft, flexible design        so that it can be manipulated to conform to the anatomy of the        patient.        Other stimulation therapies or implementations of the        implantable stimulation system 10 can cause some or all of these        criteria to be changed or adjusted, and also for certain        criteria to be added or removed.

To meet these criteria, receiving antenna 32 can have a double-layer,flat, “pancake” configuration. Referring to FIG. 4 , antenna 32 can havea flexible PCB construction in which first or upper/top antenna coil 34is formed on a first or upper/top side of substrate 38 and second orlower/bottom antenna coil 36 is formed on a second or lower/bottom sideof the substrate. Substrate 38 can be a thin (e.g., 1 to 3 mil)polyimide layer and coils 34, 36 can be etched from thin layers ofcopper or gold (e.g., 1 oz./ft²≈1.4 mil) laminated onto substrate 38.

PCB 38 can also support electronic components 52 in electronics package50. Using guidelines for maximum permissible magnetic field exposure,IEEE Standard C95.1-2005 (which is incorporated herein by reference inits entirety), the maximum achievable delivered power is approximately10-30 mW at 6.78 MHz frequency. These power requirements were chosenbased on the estimated requirements for components 52 of electronicspackage 50, the estimated maximum stimulation parameters, andpre-clinical studies, while also including a safety factor to allow forcapacitor charging and to provide transitional power. Transitional powercan be provided via a variety of components, such as capacitors,supercapacitors, ultracapacitors, or even a rechargeable power source,such as a battery. Continuous power during patient movement, especiallyat the high end of power ratios and/or when coupling is not ideal. Thetransitional power source helps ensure complete, continuous operation ofthe neuromodulation device 20, even during patient movement.

Those skilled in the art will appreciate that, in operation, an antennacan be susceptible to power losses due to substrate losses and parasiticcapacitance between coils 34, 36 and between the individual coil turns.Substrate losses occur due to eddy currents in the substrate due to thenon-zero resistance of the substrate material. Parasitic capacitanceoccurs when these adjacent components are at different voltages,creating an electric field that results in a stored charge. All circuitelements possess this internal capacitance, which can cause theirbehavior to depart from that of “ideal” circuit elements.

Advantageously, antenna 32 can implement a unique two-layer, pancakestyle coil configuration in which coils 34, 36 are configured inparallel. As a result, coils 34, 36 can generate an equal orsubstantially equal induced voltage potential when subjected to anelectromagnetic field. This can help to equalize the voltage of coils34, 36 during use, and has been shown to significantly reduce theparasitic capacitance of antenna 32. In this parallel coil configurationof antenna 32, top and bottom coils 34, 36 are shorted together withineach turn. This design has been found to retain the benefit of lowerseries resistance in a two-layer design while, at the same time, greatlyreducing the parasitic capacitance and producing a high maximum poweroutput.

This improved, parallel configuration of antenna 32 is illustrated inFIGS. 7A and 7B, which illustrate the top and bottom coils 34 and 36,respectively, on PCB substrate 38. Each coil 34, 36 can include aplurality of coil windings or turns 40 and can be characterized by thefollowing properties: number of turns (N), outside diameter (OD), coilpitch (P), trace width (W), trace thickness (T), and coil spacing (S).These properties are measured as follows:

-   -   The OD is the diameter of coil 34, 36 measured across the coil        between outer edges of outermost turn 40.    -   The coil pitch P is the spacing between turns 40 measured        between any two adjacent turns.    -   The coil width W is the width of each coil turn 40.    -   The trace thickness T is the thickness of turns 40, which is        determined by the thickness of the conductive (Cu) layers        laminated onto substrate 38 in the PCB construction.    -   The coil spacing S is the distance between coils 34, 36, which        is determined by the thickness of substrate 38 in the PCB        construction.

In one particular configuration of antenna 32, PCB substrate 38 is a 2mil polyimide layer and coils 34, 36 are etched from 1.4 mil copperlaminated onto the substrate. The parallel coil configuration of theantenna 32 results from electrically connecting the turns 40 of thecoils 34, 36 through substrate 38. These connections can be in the formof electrically conductive connectors illustrated at 42 in FIGS. 9A and9B. Connectors 42 between the turns 40 can, for example, be formed bydrilling or laser etching holes through the PCB structure, e.g., throughsubstrate 38 and turns 40 of the upper and lower coils 34, 36, andplating or filling the holes with a metal, such as plated copper/gold ormelted and/or flowed tin-lead, for example, to electrically connect theturns on the opposite surfaces of the substrate. The connectors couldalso be formed mechanically, e.g., pins or rivets.

Coils 34, 36 of antenna 32 have a unique configuration that allows fortheir parallel interconnection. On each side of antenna 32, turns 40 aresemi-circular, each having a fixed diameter with closely spaced ends.This is opposed to a traditional coil configuration in which thediameter of the turns varies continuously in a spiral that decreasesprogressively from outside to inside. To create the coiled configurationof the antenna 32, on one side of the antenna (upper coil 34 side in theexample configuration of FIG. 7A), links 44 can extend diagonallybetween adjacent turns 40 of upper coil 34. Links 44 can be formed asportions of the copper layer, for example, laminated onto substrate 38,and therefore can be formed coextensively with turns 40 of upper coil 34as one continuous conductive (Cu) strip. Upper coil 34 can therefore beconfigured as a continuous coil having decreasing diameter from outsideto inside and can therefore function as a spirally configured coil.

On the lower coil 36 side of antenna 32, turns 40 can also besemi-circular, each having a fixed diameter with closely spaced ends.There can be no links connecting adjacent turns 40 of lower coil 36.Instead, on the lower coil 36 side of antenna 32, terminals 46 can beformed—one connected to a terminal end of the innermost turn of thelower coil, and one connected to a terminal end of the outermost turn ofthe lower coil. Terminals 46 can be connected to innermost turn 40 andcan extend in the space between the ends of the remaining turns.

Viewing FIGS. 7A and 7B, turns 40 of upper and lower coils 34, 36 can beinterconnected at each of connectors 42. Through connectors 42, thelinks 44 interconnecting the adjacent turns 40 of the upper coil 34 canalso interconnect the adjacent turns of lower coil 36. Thus, turns 40 ofthe lower coil 36 also can be arranged in a continuous coiledconfiguration through connectors 42 and links 44. Lower coil 36therefore can be configured as a continuous coil having decreasingdiameter from outside to inside and can therefore function as a spirallyconfigured coil.

Terminals 46 can be electrically connected to both upper coil 34 andlower coil 36 through connectors 42. The terminal ends from whichterminals 46 extend can be radially opposite ends of inner and outerturns 40. As shown, terminal 46 of innermost turn 40 is connected to afirst end of the turn, on a first side of the space between the oppositeends of the turns; whereas the terminal of outermost turn 40 isconnected to an opposite second end of the turn, on an opposite secondside of the space between the opposite ends of the turns.

For the configuration illustrated in FIGS. 7A and 7B, the performance ofthe antenna can depend on the properties listed above. Exampleconfigurations of the antenna, for which some of these properties wereadjusted, were tested. These example configurations are illustrated inthe following table:

Example Example Example Example Property 1 2 3 4 Outer Diameter 30 mm 30mm 30 mm 26 mm (OD) # Turns (N) 12 10 8 10 Coil Pitch (P) 1.0 mm 1.0 mm1.0 mm 1.0 mm Trace Width (W) 0.5 mm 0.5 mm 0.5 mm 0.5 mm TraceThickness 1.4 mil 1.4 mil 1.4 mil 1.4 mil (T) Coil Spacing (S) 2 mil 2mil 2 mil 2 mil Max. Power 32.0 mW 39.4 mW 43.7 mW 23.3 mW DeliveryAs shown in the above table, the maximum power delivered provided byeach example coil configuration met or exceeded the 10-30 mW powerrequirement, even with the reduced coil outside diameter of Example 4.

The external controller 100 can have two components: power mat 110 andbedside control unit 120. Control unit 120 can be connected to power mat110 by wire, for example, and is designed to be placed bedside, e.g., ona nightstand. The control unit can include a user interface, e.g.,buttons, knobs, touchscreen, etc., to allow the user to controloperation of the system when using the system in bed. Power mat 110 canbe designed to be placed on the sleeping surface, such as a bedmattress, and therefore can be configured to have the form of a pad,e.g., a thin, flat, soft, flexible and non-slip configuration. Power mat110 supports one or more wireless power transmit coils 112 in or on aflexible or semi-flexible surface 114. Power mat 110 can be positionedon the sleeping surface so that a lower edge 116 of the mat correspondsapproximately to the position of the patient's shoulders while sleeping.The shape and size of the power mat 110 can correspond, for example, tothat of a pillow, such as a queen size pillow.

Control unit 120 can excite power transmit coils 112 to generate anelectromagnetic field. External controller 100 can utilize transmitcoils 112 in power mat 110 to provide tethered wireless power transferto neuromodulation device 20 by way of receiving antenna 32 throughelectromagnetic induction. When the patient is in the sleeping positionon the sleeping surface, antenna 32 of neuromodulation device 20 can bepositioned within the electromagnetic field produced by transmit coils112 of power mat 110. The shape of the field can be tailored through theconfiguration of the coils 112 to provide a field that is optimized forpowering the neuromodulation device 20 through various sleepingpositions. For example, the field can be configured extend horizontally(as viewed in FIGS. 8A-C) between the coils 112, so that theneuromodulation device 20 can be powered any time it is positionedwithin the vertical bounds of the horizontally extending field.

Through induction, electric current can be induced in receiving antenna32 and that current can be provided to neuromodulation deviceelectronics package 50. Components 52 in electronics package 50 controlthe operation of the electrical contacts. Through this operation,electrical contacts 29 can be utilized as stimulating electrodes forapplying electrical stimulation to nerves or muscles, for example andelectrical contacts 35 can be used as EMG sensing electrodes, forexample, for detecting a neuromuscular response, to the application ofelectrical stimulation.

In addition to providing power to neuromodulation device 20, externalcontroller 100 can also provide a data link for facilitating two-waycommunication between the controller and the neuromodulation device.While powering the neuromodulation device, controller 100 cansimultaneously provide a wireless data signal that is used to programthe neuromodulation device with settings, such stimulation parameters,and also retrieve stored data from the neuromodulation device, such astriggered stimulation events, measured EMG responses or other electricalphysiological signals, current values, electrode impedances, and datarelated to the wireless power transfer between controller 100 andneuromodulation device 20.

Additionally, the neuromodulation device 20 can monitor the impedanceand/or voltage of the neuromodulation device antenna 32 so that thepower supplied to the neuromodulation device can be calculated. This canbe provided as feedback to the controller 100 that allows the controllerto adjust the current supplied to the power transmit coils 112. Thecontroller 100 can control the power delivered to the neuromodulationdevice so as to remain within the standards/requirements set forthabove. At the same time, the feedback can also facilitate increasing thecurrent supplied to the power transmit coils 112 so that adequate powertransfer to the neuromodulation device 20 is maintained, again withinthe prescribed limits. In this manner, the controller 100 can implementclosed-loop control to optimize the power supplied to theneuromodulation device 20.

The operation of the controller 100 can be controlled through the userinterface 200, which allows the user, e.g., the patient, physician orother caretaker, to control aspects of the operation of the implantablestimulation system 10. The control can be local, e.g., by the patientusing a user interface of the control unit 120 or the patient userinterface 200, or remote, e.g., by the physician through internet/cloud208. The control unit 120 can have a small footprint and power mat 110can be flexible in design so that external controller 100 is small,discreet, and portable for travel purposes.

Power Mat Configuration

To account for varying sleeping positions throughout the night, powermat 110 can have a large enough footprint to allow patient movementwhile still maintaining the ability to transmit power to neuromodulationdevice 20. At the same time, external controller 100 does produceelectromagnetic radiation at a level that falls outside the guidelinesfor maximum permissible magnetic field exposure as recommended in IEEEStandard C95.1-2005 (Reference 3).

Example transmit coil configurations that can be implemented in powermat 110 are illustrated in FIGS. 8A-8C. These example transmit coilconfigurations can be implemented with a flex circuit design, i.e., thecoils can be formed (e.g., etched) from a conductive metal (e.g., copperor gold) laminated on a flexible substrate (e.g., polyimide). Theexamples of FIGS. 8A-8C illustrate the overall shape of transmit coils112 without showing the individual turns of the transmit coils. This isbecause the properties of the transmit coils 112, e.g., the number ofturns, coil pitch/spacing, trace width, etc. is not limited, as can bethe case with coils 34, 36 of antenna 32. Antenna coils 34, 36 can betailored specifically for maximum induced power generation due to thesmall footprint limitations of antenna 32 of neuromodulation device 20.Power mat 110 can be larger in comparison and transmit coils 112 can befree to be configured to produce a magnetic field that can be limitedonly by requiring a level that falls within the IEEE magnetic fieldexposure guidelines mentioned previously.

Accordingly, transmit coils 112 can be configured to maximize the spaceor volume that the magnetic field covers so as to allow for variationsin the patient position during sleep. This can give the system theability to continuously power the neuromodulation device through avariety of sleeping positions throughout the night. FIG. 8A shows atwelve coil example configuration of transmit coils 112; FIG. 8B shows atwo coil example configuration of transmit coils; and FIG. 8C shows afour coil example configuration of transmit coils. For all of theseexample configurations, experimental testing showed that transmit coils112 are capable of meeting the system power requirements, within theIEEE exposure guidelines, while allowing for consistent power transferto the antenna 32 over an effective volume of approximately 32×76×25 cm(L×W×H), which was found to be sufficient to cover the patient during anormal sleep cycle.

The twelve coil configuration of transmit coils 112 in FIG. 8A can allowfor dynamic control of the magnetic field produced by the power mat 110.Through data coupling and communication between external controller 100with neuromodulation device 20, a determination can be made as to whichcoil(s) of the twelve coil configuration are effectuating the powercoupling between the external controller and the neuromodulation device.Through this determination, the external controller 100 can power onlythose coils necessary to power neuromodulation device 20, given thecurrent position of the patient relative to power mat 110. As thepatient changes positions, the neuromodulation device can detect anydecrease in power transmission, which can trigger a reassessment and theselection of different coil(s). This configuration can thus beself-tuning, on-the-fly to maximize the electromagnetic field producedby the power mat 110 in the area of the antenna 32.

The two coil configuration of the transmit coils 112 in FIG. 8B can bestatic power coils that produce a continuous electromagnetic fieldaround power mat 110. This configuration can be tuned to maximize theelectromagnetic field strength in the largest possible volume so thatpower transmission is maximized throughout a wide variety of patientpositions.

In the example configurations of both FIG. 8A and FIG. 8B, power mat 110can have a flexible construction facilitated by a flexible circuitconstruction of transmit coils 112 housed within a flexible cover, suchas, for example, soft plastic, rubber, fabric, etc. Transmit coils 112can, for example, have a flexible PCB construction similar to antenna 32of neuromodulation device 20. For instance, transmit coils 112 can beconstructed as a single layer flexible PCB, with conductive tracesetched from copper, for example, laminated on a polyimide, for example,substrate.

Each of the disclosed aspects and embodiments of the present disclosuremay be considered individually or in combination with other aspects,embodiments, and variations of the disclosure. Further, while certainfeatures of embodiments and aspects of the present disclosure may beshown in only certain figures or otherwise described in the certainparts of the disclosure, such features can be incorporated into otherembodiments and aspects shown in other figures or other parts of thedisclosure. Along the same lines, certain features of embodiments andaspects of the present disclosure that are shown in certain figures orotherwise described in certain parts of the disclosure can be optionalor deleted from such embodiments and aspects. Additionally, whendescribing a range, all points within that range are included in thisdisclosure. Furthermore, all references cited herein are incorporated byreference in their entirety.

What is claimed is:
 1. A neuromodulation system comprising: an antennaconfigured to produce an induced current in response to being disposedin an electromagnetic field; a stimulation lead extending from aproximal end at the antenna to a free distal end, the stimulation leadhaving a stimulating electrical contact disposed thereon and configuredto be implanted adjacent to a stimulation site between a geniohyoidmuscle of a patient and a genioglossus muscle of the patient, thestimulating electrical contact being configured to deliver a stimulationsignal to either a right hypoglossal nerve of the patient or a lefthypoglossal nerve of the patient; a sensing lead comprising a sensinglead body extending from a proximal end at the antenna to a free distalend, the sensing lead body comprising a proximal portion and a distalportion, the proximal portion extending between the proximal end of thesensing lead body and the distal portion and the distal portioncomprising a left region, a right region, and an intermediate regiontherebetween, the left region having a left sensing contact disposedthereon and the right region having a right sensing contact disposedthereon, wherein the distal portion of the sensing lead body isconfigured to be implanted between the genioglossus muscle and thegeniohyoid muscle and adjacent to a sensing site such that the leftsensing contact is positioned at a left side of the genioglossus muscleand the right sensing contact is positioned at a right side of thegenioglossus muscle, the left and right sensing contacts beingconfigured to record physiological signals from the sensing site,wherein the intermediate region comprises a bend that positions theintermediate region in a different plane than the left and right regionssuch that when the distal portion of the sensing lead body is placedbetween the geniohyoid muscle and the genioglossus muscle, theintermediate region is inferior of the left and right regions and pushesthe left sensing contact and the right sensing contact cranially intothe genioglossus muscle; an electronics assembly comprising electricalcomponents to generate the stimulation signal and to control theapplication of the stimulation signal via the stimulating electricalcontact of the stimulation lead and sensing of the physiological signalsvia the left and right sensing contacts; an external controllercomprising a control unit and a power transducer that supports a powertransmission coil that is excitable to produce the electromagnetic fieldfor inducing electrical current in the antenna to power the electronicsassembly; and an internal computing device comprising: a non-transitorymemory storing instructions; and a processor to access thenon-transitory memory and execute the instructions to at least: monitorthe physiological signals recorded by the left and right sensingcontacts; identify a trigger within the physiological signals, whereinthe trigger is identified as a biomarker for a condition related tosleep; and apply a rule-based classification to the trigger to determinewhether one or more parameters of the stimulation signal should bealtered based on the biomarker and to alter the one or more parametersof the stimulation signal in response to the biomarker.
 2. Theneuromodulation system of claim 1, wherein the stimulation lead is afirst stimulation lead and the stimulating electrical contact is a firststimulating electrical contact, the system further comprising a secondstimulation lead extending from a proximal end at the antenna to a freedistal end, the second stimulation lead having a second stimulatingelectrical contact disposed thereon and configured to be implantedadjacent to a second stimulation site between a geniohyoid muscle of thepatient and a genioglossus muscle of the patient, the second stimulatingelectrical contact being configured to deliver a second stimulationsignal to the other of the right hypoglossal nerve or the lefthypoglossal nerve.
 3. The neuromodulation system of claim 2, wherein:the first stimulation lead has a first cuff body comprising the firststimulating electrical contact disposed thereon; the second stimulationlead has a second cuff body comprising the second stimulating electricalcontact disposed thereon; and the sensing lead comprises a plurality ofsensing contacts disposed thereon.
 4. The neuromodulation system ofclaim 1, wherein the stimulation lead comprises: a first cuff body sizedand configured to at least partially wrap around a first nerve branchsite comprising a hypoglossal nerve branch distal to a hypoglossal nervetrunk of the either of the right hypoglossal nerve of the patient or theleft hypoglossal nerve of the patient; and a second cuff body sized andconfigured to at least partially wrap around a second nerve branch siteproximal to the first nerve branch site.
 5. The neuromodulation systemof claim 1, wherein the stimulation lead and the sensing lead areoperably coupled to the electronics assembly and the electronicsassembly is operably coupled to the antenna, the antenna configured tosupply the induced electrical current to the electronics assembly topower the electronics assembly.
 6. The neuromodulation system of claim5, wherein the stimulation lead, the sensing lead, the electronicsassembly, and the antenna form a single neuromodulation device, theantenna located at a proximal end of the neuromodulation device, theelectronics assembly operably coupled to the antenna, and thestimulation lead and sensing lead extending distally away from theelectronics assembly.
 7. The neuromodulation system of claim 1, wherein:the intermediate region defines an apex of the sensing lead body; andthe sensing lead body is biased towards an omega shape when the sensinglead is fully deployed within the patient and the intermediate region ofthe sensing lead body is biased towards an inferior position relative tothe left and right regions when the sensing lead is fully deployed. 8.The neuromodulation system of claim 1, wherein the power transducer is amat configured to be positioned between a sleeping surface and thepatient.
 9. The neuromodulation system of claim 1, wherein the antennacomprises an upper coil and a lower coil electrically connected to eachother in parallel.
 10. The neuromodulation system of claim 1, whereinthe left and right sensing contacts are EMG sensors and thephysiological signals are obtained from EMG activity from thegenioglossus muscle.
 11. The neuromodulation system of claim 1, whereinrules of the rule-based classification are adaptive.
 12. Theneuromodulation system of claim 1, wherein the trigger indicates achange in phasic and/or tonic genioglossus muscle activity duringrespiration.
 13. The neuromodulation system of claim 1, furthercomprising a connector having a proximal end and a distal end, theantenna being electrically coupled to the stimulation lead and thesensing lead via the connector, and wherein the distal end of theconnector is coupled to the proximal end of the sensing lead body.
 14. Amethod of improving sleep disordered breathing in a patient sufferingtherefrom comprising: providing the neuromodulation system of claim 1;placing the stimulating electrical contact adjacent to theft stimulationsite between the geniohyoid muscle of the patient and the genioglossusmuscle of the patient, the stimulation site comprising a nerve trunk ofthe right hypoglossal nerve of the patient or the left hypoglossal nerveof the patient, a lateral branch of the right hypoglossal nerve of thepatient or the left hypoglossal nerve of the patient, a medial branch ofthe right hypoglossal nerve of the patient or the left hypoglossal nerveof the patient, or suitable combinations thereof; placing the distalportion of the sensing lead body adjacent to the sensing site such thatthe left sensing contact is positioned at the left side of thegenioglossus muscle and the right sensing contact is positioned at theright side of the genioglossus muscle; activating the left sensingcontact and the right sensing contact to record the physiologicalsignals from the sensing site; and activating the stimulating electricalcontact to deliver the stimulation signal to either the righthypoglossal nerve of the patient or the left hypoglossal nerve of thepatient based on the recorded physiological signals to improve thepatient's sleep disordered breathing.